Refrigerating apparatus



Oct. 25, 1938.- B. M. BUCHANAN REFRIGERATING APPARATUS Filed June 26,1936 INVENTOR F 'a' Lssu: B.M.BucHn-/a-.

BY 7/ ATTORN Y WIT ESSES:

Patented Oct. 25, 1938 BEFBIGEBATIN G APPARATUS Leslie B. M. Buchanan,Springfield, Mala, as slgnor to Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., acorporation of Pennsylvania ApplicationJune 2c, 1936, Serial No. 81,424

19 Claims.

My invention relates to refrigerating apparatus of the type employing aplurality of'evaporator elements operated at dlflerent mean temperaturesand has for an object to provide improved apparatus of this character.

A further object of the invention is to'provide I an improved domestictype refrigerator and method of refrigeration wherein fluids may be morerapidly congealed than in prior apparatus of this kind.

A still further object of the invention is to effect quick freezing ofwater or other fluids in a conventional refrigerator cabinet withoutdepressing the temperature of the food storage com- 16 partment to anundesirable degree and without excessively dehydrating the air therein.

A further object of my invention is to refrigerate one element of. arefrigerating system to a relatively low temperature, prior to therefrigera- 20 tion of a second element at a higher temperature duringeach cycle of the system.

These and other objects are eifected by my in- :vention, as will beapparent from the following description and claims taken in connectionwith '25 the accompanying drawing, forming a part of this application,in which:

Fig. 1 is a sectional view of a portion of a domestic refrigeratorhaving my improved refrigerating apparatus applied thereto; 30 Fig. 2 isaview of a detail of Fig. 1 shown in a diii'erent operating position;

Fig. 3 is a section of the detail shown in Fig.2 and is taken along theline III--III of Fig. 1; and, Fig. 4 is a modified view of some of thedetails 35 shown in Fig. 1.

In prior refrigerating machines of the domestic type having a foodstoragecompartment and a common evaporator therein for cooling the airin the compartment and for freezing fluids, quick 40 freezing of thelatter without excessively dehumidifying and cooling the air in thecompartment has been difllcult. If the temperature of the evaporator ismaintained at a desirable value for cooling the food in the compartment.then con- 45 gealing'of fluids is slow and, if the temperature of theevaporator is lowered to eii'ect quick congelatlon, then excessivecooling of the food and' dehydration of the same is experienced.

To obviate this undesirable condition, it has 50 been proposed to supplydifferent compartments I for food cooling and for congealing of fluidsor freezing of water. Separate evaporator elements are provided for therespective compartments, which evaporators operate at different tempera-55 tures suitable for these purposes. construc- (Cllit-4) tion, whileeffective, is expensive. My invention may be applied to-a cabinetconstruction such as this, but may'a'lso be applied to the lessexpensive type of construction wherein a single insulated food storagecompartment is employed 5 with a unitary refrigerating element foreffecting the refrigeration of both the food products and the fluid tobe congealed.

In practicing my invention, an evaporator structure may be disposed in asingle compart- 10 ment of the refrigerator which structure may take theoutward appearance of a conventional evaporator. The walls of theevaporator structure and freezing trays define relatively high and lowtemperature evaporator elements. The walls are arranged in heatexchanging relation with the air in the compartment and the shelves aredisposed within the walls and are shielded thereby from the air withinthe compartment.

In accordance with my invention, a conventional refrigerant condensingunit circulates refrigerant through the evaporating elements, preferablyin series, so that refrigerant flows through the shelves and thencethrough the walls. Va-

porized refrlgerantiis withdrawn from the walls.

A reservoir for the storage of condensed refrigerant is connected to theshelves and walls,'preferably between these elements. The purpose of thereservoir is to store more or less condensed refrigerant, so that it mayor may not be delivso ered to the wall members for vaporization therein.A thermostatically operated device responsive to the temperature of therefrigerant d'elivered to the reservoir by the shelves or lowtemperature' evaporator element, controls the storage of refrigerant inthe reservoir.

The circulation of refrigerant is preferably controlled in response tothe temperature of the walls or high temperature element. When the wallsattain a predetermined high temperature, 40 refrigerant is delivered tothe shelves and thence to the reservoir. At this time, refrigerant isstored in the reservoir due to the relatively high temperature of therefrigerant therein. so that no refrigerant is delivered forvaporization in the wall members. when the shelves are depressed to alow temperature. the, thermostatic control in the reservoir dischargesthe stored refrigerant, to the walls for vaporization therein. As thetemperature of the latter is depressedfto the desired value,thecondensin'g unit is stopped and refrigeration of both elements isterminated.

During the inactive periods of the condensing unit, the thermostaticdevice in the reservoir operates at a predetermined temperature tocondition the reservoir for storage of refrigerant therein. Thereafter,when the condensing unit is started at a predetermined highertemperature, the cycle is repeated. Accordingly, when the condensingunit starts, the shelves are first refrigerated to a relatively lowtemperature and, thereafter, the walls are refrigerated to a relativelyhigher temperature.

Reference will now be had to Fig. 1 of the drawing which disclosesrefrigerating apparatus constructed in accordance with one form of myinvention applied to a conventional cabinet ||l having a compartment forthe storage of articles to be refrigerated. A refrigerant evaporatingstructure, generally indicated at I2, is disposed within the compartmentfor cooling the air therein and for fluid congealing purposes such as,for example, the freezing of water. The structure |2 includes side wallsl3 and I4 that are provided with spaces l5 and I6, respectively, forrefrigerant. A bottom wall |1 connects the bottoms of the side walls l3and I4 and may or may not be refrigerated. A passage IB is disclosed inthe bottom wall H for conducting refrigerant from the wall |3 to thewall M. The upper portion of the wall |4 includes a header l9 from whichrefrigerant vaporized in the structure I2 is withdrawn.

The evaporating structure |2 may be suspended in the compartmentpreferably by extensions 20 of the Walls l3 and H. The side and bottomwalls define a chamber 2| therebetween which may be closed at the backby a rear wall 22. The rear wall 22-is connected to the side walls l3and I4 and preferably extends from the bottom wall H to the top of theextensions 20.

The front of the chamber 2| may be closed by a door (not shown) in awell understood manner.

Arranged within the chamber 2| are shelves 23 and 24 having respectivepassages 25 and 26 formed therein for refrigerant. A conduit 21 isemployed for conducting condensed refrigerant to the shelf passage 25and a conduit 28 provides communication between the shelf passages 25and 26. These connections provide for series flow of refrigerant throughthe shelves 23 and 24, but it will be understood that other methods ofconducting refrigerant through the shelves may be employed. Trays 29 maybe supported by the shelves for the fluid to be congealed or frozen.

The walls l3 and I4 define an evaporating element that is maintained ata mean temperature suitable for refrigerating the air within thecompartment to a temperature value that is optimum for the storage offood. This value is sumciently low for proper cooling of the air andhigh enough to prevent excessive dehydration thereof. The shelves 23 and24 define an evaporating element that is maintained at a lower meantemperature than the walls l3 and I4, so that faster freezing of fluidin the'trays 29 is obtained than would be obtained at the higher meanwall temperature.

and walls of the evaporating structure |2 by any suitable refrigeratingmachine such as, for example, a hermetically sealed mot r drivencompressor mechanism 3|. The mechanism 3| withdraws vaporizedrefrigerant from the header l9 through a conduit 32 and compresses it toa relatively high value for delivery through a conduit 33 to a condensershown diagrammatically at 34. Cooling of the condenser 34 is effected inany suitable manner for lique'fying the compressed vapor. Condensedrefrigerant is delivered to the conduit 21 through a suitable pressurereducing device such as a conventional high side float valve 35. Theoperation of a system of the compressor-condenser-expander cycle is wellknown and no'description thereof is deemed necessary. e

The motor compressor mechanism 3| is energized by electrical lineconductors L1 and La controlled by a thermostatic switch 36 preferablyresponsive to the temperature of the wall I4. I disclose a thermostaticswitch 36 of the expansible gas type, but it will be understood anysuitable thermostatically operated switch may be employed. As shown, theswitch 36 includes a temperature-responsive element 31 secured to thewall |4 adjacent the header [9. As the operation of gas typethermostatic switches is well known, no detailed description of theoperation will be given other than to state that the switch is closed ata relatively high temperature of the wall l4 and is opened at arelatively low temperature thereof.

In accordance with my invention, means are provided for reducing thetemperature of the shelves 23 and 24 to a relatively low degree eachtime the compressor mechanism 3| is operated to effect cooling of thewalls I3 and I4 and, therefore, the air within the compartment II. Thisoperation is effected by, first, evaporating refrigerant in the shelvesand. subsequently, effecting evaporation in the walls.

The means for accomplishing this operation includes a structure 40 thatdefines a reservoir 4| for storing variable quantities of condensedrefrigerant (Figs. 1 to 3, inclusive). A conduit 42 is provided forconducting condensed and vaporous refrigerant from the shelf passage 28to the reservoir 4| and a second conduit 43 provides communicationbetween the reservoir 4| and the passage |5 of the wall l3. The latterconduit 43 defines an overflow device and may extend upwardly in thereservoir a predetermined distance for determining the maximum depth andquantity of refrigerant to be stored therein, as shown in Fig. 1.

An inverted cup 44 is disposed coaxially with the conduit in telescopicrelation and is supported by a thermostatic member or disc 45. Thelatter may be of bi-metal construction with the high expansive metal ontop, so that, when it is relatively warm, it is in the position shown inFig. 1, and, when cooled, it snaps to a position in which it is curvedin the opposite direction to that shown. Accordingly, the cup 44 islowered into the refrigerant as shown in Fig. 2, whereby the depth andquantity of the refrigerant in the reservoir 4| is reduced as describedhereinafter. The disc 45 may be supported in any suitable manner as bylugs 45 formed within the reservoir structure 40.

The discharge end of the conduit 42 is disposed adjacent thethermostatic disc 45 whereby refrigerant entering the reservoirstructure 4|! flows in heat-exchanging relation over the disc 45 andthen drops to the reservoir 4 The disc 45, therefore, is operated inresponse-to the temperature of the refrigerant entering the reservoir.4|.

I tively small, the amount of heat abstracted from When this temperatureis at a relatively high value, the disc 45' is in its upper position andthe maximum quantity of refrigerant, as determined by the elevation ofthe open end of the overflow conduit 43, is stored in the reservoir 4|.When the temperature of the refrigerant entering the reservoir 4| is ata relatively low value, the disc 45 snaps downwardly to the positionshown in Fig. 2 and the cup assumes a lowered position in which it istelescoped with the conduit 43. As the cup 44 is of larger insidediameter than the outside diameter of the conduit 43, an annular passageis defined therebetween, which passage provides communication betweenthe reservoir 4| and the conduit 43.

The conduit 43 is connected to the suction of the compressor unit 3|through the walls l3 and I4, so that a lower-pressure prevails in theconduit 43 than in the reservoir 4|. Condensed refrigerant will,therefore, rise in the annular passage between the cup 44 and theconduit 43 and overflow into the latter until the level of the condensedrefrigerant in the reservoir 4| is depressed slightly below the bottomof-the cup. This level determines the minimum depth and quantity ofrefrigerant stored in the reservoir 4|. At this time, the walls l3 and Hare filled with refrigerant, the level of which is indicated by the dotand dash line in the header IS. (Fig. 1.)

When the maximum quantity of refrigerant is stored in the reservoir(Fig. 1) the walls l3 are devoid, substantially, of condensedrefrigerant so that evaporation is efiected only within the shelves 23and 24. When the reservoir contains its minimum quantity of refrigerant,the walls l3 and I4 contain condensed refrigerant in an amountrepresented by the difference in quantities of refrigerant stored by thereservoir and evaporation at this time is eifected in the wall membersl3 and I4.

Operation closes for initiating operation of the motor compressor unit3|.

Condensed refrigerant from the condenser passes to the shelves 23 and 24through the float valve 35 and is vaporized in the shelves forabstracting heat from the material in the trays 29 in a well understoodmanner. Excess condensed refrigerant passed to the shelves, of course,passes through conduit 42 and, after contacting the disc.

45, collects in the reservoir 4|. Vaporous refrigerant from the shelfpassages 25 and 26 passes through the conduit 42, the reservoirstructure 40,

conduit 43, passages |3 .|8 and I6 of the walls to the header I9 andthence to the compressor unit 3| through conduit 32. Refrigeration isnow effected in the shelf passages .25 and 26 by evaporation and nocooling is eifected by-evaporation in the wall passages l5 and I8. Somecooling of the walls l3 and I4 will befleflected but it is relathe wallsbeing only that added to therei'rigerant vapor as superheat. j

Some evaporation is effected in the reservoir structure 40, but this maybe reduced by covering the structure with heat insulation (not shown). IIn any event, the cooling efiect of the evaporation in the reservoir 4|is confined to the air in the chamber 2| containing the trays 29. I

During this operation, the temperature of the shelves 23 and 25 isdepressed with little reduction in temperature of the walls l3 and I4.As the temperature of the refrigerant contacting the bimetal disc 45reaches a. low value of 10 degrees, for example, the disc 45 and cup 44snap downwardly, as shown in Fig. 2, the refrigerant level in thereservoir descends; the outflowing condensed refrigerant filling thewall passages l5 and IE to a level shown in dotted lines in the headerl9. Evaporation is immediately effected in the wall passages l5 and I6for cooling the air in the food compartment As refrigeration of thewalls is initiated, the pressure-and temperature of the refrigerant inthe low side of the system rises due to the rapid evaporation obtainingin the wall passages; Ac-' cordingly, as the walls are cooled, thetemperature of the refrigerant in the shelves rises to a storage ofrefrigerant when operation of the compressor unit 3| is started, whichoperation is effected when the temperature; of the wall |4 rises to 29degrees. 1

From the foregoing, it will be apparent that the shelves are operated ata lower mean temperature than the wall members; the former operating inthe example recited between 29 degrees and 10 degrees and the wallmembers between 29 degrees and 16 degrees. By reducing the shelves.to-the relative low temperature of 10'- degrees each time the system iscycled, fast freezing or congelation of substances in the trays iseffected. As the walls are operated at a higher minimum temperature or16 degrees, and since. the walls shield the shelves, it will be apparentless dehydration of 'the air in the compartment is obtained in my systemthan in conventional systems wherein the walls and shelves 'are operatedat substantially the same lower temperatures.

Fig. 4 discloses a-second embodimentof the arrangement of the reservoirin the evaporator snaps upwardly to condition the reservoir for Istructure. In this embodiment, the separate reservoir structure 4.0 ofFig. 1 is replacedby a structum-5t formed at the top of the wall |3.-The operation of the two embodiments is similar so that no furtherdescription is necessary and parts which may be common to both areindicated by like numerals in bothiflgures of the -drawing.

In Fig. 4, however, -I have shown heat insulation 5| disposed on theside of the reservoir 5 that is exposed to the air in the compartment H.The insulation is employed forvrestrictingithe flow of heat to thereservoir structure 50 from the air in the compartment I during periodswhen the shelves onlyare refrigerated, at which time the reservoirstructure 50 would assume, substantially, the

relatively low temperature of the she was I lie I have disclosed myimproved apparatus including a structure wherein the low temperatureevaporating element is within and shielded by the higher temperatureelement,- it is tobe understood that these elements may be separated ordisposed in separated compartments without departing from the spirit andscope of my invention.

While I have shown my invention in but two forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be plaeedthereupon as are imposed by the prior art or as arespecifically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of first and secondevaporating elements, means for condensing refrigerant vaporized in saidelements, means for conveying liquid refrigerant of refrigerantcondensing means, an evaporator structure having first and secondevaporating elements, means for conveying the condensed refrigerant tosaid evaporator structure, a reservoir for condensed refrigerant, and athermostatically operated device arranged within the reservoir forvarying the supply of refrigerant therein and movable, to a firstposition, wherein a relatively large amount of condensed-refrigerantisstored in the reservoir and substantially no condensed refrigerant isdelivered to the second evaporating element and movable, to a secondposition, wherein a relatively small amount of refrigerant is stored inthe reservoir and condensed refrigerant is delivered to both of saidevaporating elements.

3. In a refrigerating systempthe combination of refrigerant-condensingmeans, an evaporator structure having first and second evaporatingelements, means for conveying the condensed refrigerant to saidevaporator structure, a reservoir carried by said evaporator structurefor storing condensed refrigerant therein, a device disposed within the,reservoir for controlling the storage of refrigerant therein,thermostatically-operated means responsive to the temperature of therefrigerant in the reservoir for actuating said device to a firstposition, wherein condensed refrig- I erant is, stored in the reservoirand substantially no condensed refrigerant is delivered to said secndevaporating element, and movable to a second I position,- whereincondensed refrigerant is discharged from the reservoir and is deliveredto both of said evaporating elements, and means responsive to thetemperature of thesecond evaporating element for-controlling theoperation of the refrigerant condensing means.

4. In a refrigerating system, the combination of refrigerantcondensingmesns, first and second refrigerant evaporating elements,means for conveying condensed refrigerant from the condensing means tosaid evaporating elements so that it flows to the first evaporatingelement in preference to the second evaporating element, a

reservoir for condensed refrigerant; thermostatic means responsive-tothe temperature of the refrigerant in the reservoir for controlling thestorage of condensed refrigerant therein, said thermostatic means beingmovable to a first position wherein condensed refrigerant collects inthe reservoir and substantially no condensed re- 1 frigerant isdelivered to the second evaporatingelement, said thermostatic meansbeing movable to a second position wherein condensed refrigerant ispassed through the reservoir to the second element for vaporizationtherein, and means I responsive to the temperature of the second element for controlling the operation of the refrigerant condensing means.

5. In a refrigerating system, the combination of refrigerant condensingmeans, first and second refrigerant evaporating elements, means forconsaid first-and second elements, a reservoir for condensed refrigerantdisposed between said first and second elements, and a thermostaticdevice responsive to the temperature of the refrigerant entering thereservoir for .controlling the storage of refrigerant therein, saiddevice being movable to a first position in response to a relativelyhigh temperature for effecting storage of condensed refrigerant in thereservoir with substantially nocondensed refrigerant being delivered tothe second evaporating element and movable to a second positioninresponse to a relatively low temperature for. passing condensedrefrigerant through the reservoir to said second element forvaporization therein.

6. In. a refrigerating system, the combination of refrigerant condensingmeans, an evaporator structure including side wall members and shelvesdisposed therebetween, said sidewalls and shelves defining a pair ofevaporating elements, a reserfrigerant entering the reservoir fromtheshelves and movable to a flrstposition in-response to a relatively hightemperature of the refrigerant for effecting storage of refrigerant inthe reservoir with substantially no condensed refrigerant beingdelivered to the sidewalls, and being movable to a second position inresponse to a relatively low temperature densed refrigerant to thesidewalls for vaporization therein.

.veying condensed refrigerant serially through of the refrigerant forpassing con- '7. In a refrigerating system, the combination ofrefrigerant condensing means, an evaporator structure having first andsecond evaporating elements and a reservoir for the storage of condensedrefrigerant, means for conveying condensed refrigerant from thecondensing means through said first evaporating element, the reservoir,and the second evaporating elementin the order named, athermostatically-operated device arranged within the reservoir forcontrolling the storage of condensed refrigerant therein and disposed inheat exchanging relation with the refrigerant entering the reservoirfrom the first evaporating element, said device being movable to afirst-position in response to a relatively high temperature foreffecting the storage of condensed refrigerant in the reservoir withsubstantially no condensed refrigerant being delivered through thereservoir to said second evaporating element for vaporization therein.

8. In refrigerating apparatus, the combination of refrigerant condensingmeans, first and second refrigerant evaporating elements, a reservoirfor condensed refrigerant, means for conveying condensed refrigerant inseries through said first element, the reservoir and said second elementin the order named, means for conveying vaporized refrigerant from thesecond evaporating element to the condensing means, a thermostaticallyoperated device responsive to the temperature of the refrigerant withinthe reservoir for controlling the storage of refrigerant therein, saiddevice being responsive to a predetermined relatively high temperaturefor effecting storage of condensed refrigerant ln'the reservoir withsubstantially no condensed refrigerant being delivered to the secondevaporating-element and being responsive to a predetermined relativelylow temperature for effecting passage of condensed refrigerant throughthe reservoir to the second evapcrating element for vaporizationtherein.

"9. In refrigerating apparatus, the combination of a cabinet structurehaving a compartment therein, a plurality of wall members defining arefrigerant evaporating element and disposed in heat exchanging relationwith the air in said compartment, a shelf disposed within said. wallmembers and defining a second evaporating element disposed within saidwall members for congealing fiuids, means defining a chamber for storingcondensed refrigerant, means for withdrawing vaporized refrigerant fromsaid wall members, means for condensing the withdrawn refrigerant andfor translating it in series through said shelf, the chamber and saidwall members in the order named, thermostatically operated meansdisposed within said chamber in heat exchanging relation with therefrigerant contained therein for controlling the storage of refrigerantin the chamber, said thermostatically operated means being responsive toa .predetermined relative1y-high temperature for effecting storage ofliquid refrigerant so. that substantially no liquid refrigerant isdelivered to the wall members and being responsive to a relatively lowtemperature for passing liquid refrigerantthrough the chamber to saidwall members for evaporation therein, and means responsive to thetemperature of the wall members for controlling the operation of thecondensing means.

10. In refrigerating apparatus, the combination of a refrigerantcirculating system in which variable quantities of refrigerant are to becirculated, a structure connected in said system and defining areservoir for storing variable quantities of liquid refrigerant, meansfor admitting refrigerant to the reservoir, an outlet conduit extendingupwardly in the reservoir and open at its top for defining the maximumdepth of refrigerant to be stored, an inverted cup telescopicallyarranged with respect" to the conduit, a thermostatic member responsiveto the temperature of the refrigerant in the reservoir for supportingsaid cup and having upper and lower positions, said member, in its upperposition, maintaining the cup elevated with respect to the conduitwhereby the maximum quantity of refrigerant, as

determined by the open top conduit, is stored in the reservoir and,inits lower position, maintaining 'the cup telescoped oh the conduit sothat the lower edge of the cup defines a. lower level of refrigerant inthe reservoir.

fying refrigerant for the'evaporating elements in response to apredetermined high temperature of the high temperature element,effecting refrigeration of the low temperature element each time thehigh temperature element calls for refrigeration, substantially reducingrefrigeration of the low temperature element and effecting refrigerationof the high temperature element when the low temperature elementissatisfied in response to a predetermined low temperature of the lowtemperature element, and stopping liquefaction of refrigerant when thehigh temperature element is satisfied in response to a predetermined lowtemperature of the high temperature element.

12. The method of cycling a refrigerating machine having relatively highand low temperature evaporating elements which comprisesliquefyingrefrigerant for the evaporating elements-in response to a predeterminedhigh temperature of the high temperature element, effectingrefrigeration of the low temperature element each time the hightemperature element calls for refrigeration, 'substantiallyreducingrefrigeration of the low temperature element-and effecting refrigerationof the high temperature element when the low temperature element issatisfied in response to a predetermined low temperature of the lowtemperature element, and stopping liquefaction of refrigerant, when thehigh temperature element is satisfied in response to a predetermined lowtemperature of thehigh temperature element, which latter low temperatureis of a highenvalue than the low temperature in response to which re-'frigeration of. o the low temperature element is stopped.

13'. The method of-cycling a refrigerating ma- Ehine having first andsecond evaporating elements which comprises. periodically circulatingliquid refrigerant to the elements, delivering a portion of thecirculated refrigerant to one of said elementsfor vaporizationandwithholding a second portion of the refrigerant from circulation eachtime the machine is started, and subsequently releasingsaidwithheld'refrigerant to the second evaporating element for vaporizationtherein when the temperature of the first evaporating element has beendepressed to a predetermined value.

14. The method of cycling a refrigerating machine having relatively highand low temperature evaporating elements which comprises liquefyingrefrigerant for the evaporating elements in response to a predeterminedhigh temperature of the high temperature element, delivering a portionof the liquefied refrigerant for vaporization in the low temperatureelement and withholding from circulation.' a second portion of theliquefied refrigerant each time the machine is cycled, subsequentlyreleasing said portion of perature of the high temperature element,which latter low temperature is of a higher .value than said temperatureat which the withheld reirig erant is released.

1 5. In refrigerating apparatus, the combination of a c'abinetstructure,an evaporator disposed within the cabinet structure and embodying wallmembers and a shelf enclosed therebyg said wall members and shelfdefining separate refrigerant. evaporating elements, a refrigerantcondensing unit, means for periodically operating the condensing unit,and means for automatically efiecting, during each operation of thecondensing unit, vaporization of refrigerant in said shelf at relativelyvlow temperature and, thereafter, in the wall members at a relativelyhigher temperature.

16. In refrigerating apparatus, the combination of a cabinet having acooling compartment therein, an evaporator structure disposed withinsaid compartment and including a pair of spaced wall members and a shelfdisposed therebetween, said wall members defining a relatively hightemperature evaporating element for cooling the air in said compartmentand said shelf defining a relatively low temperature evaporating elementfor congealing fluids, a refrigerant condensing unit, means forperiodically effectingoperation of the condensing unit, and meansautomatically actuated each time the condensing unit is operated, foreffecting vaporization of refrigerant first in the shelf and,subsequently, in the wall members.

17. In refrigerating apparatus, the combination of a cabinet structure,an evaporator disposed within the cabinet structure, said evaporatorstructure embodying wall'members defining a relatively high temperatureevaporating element and a shelf enclosed by the wall members anddefining a relatively lowtemperature evaporating element, a mechanismfor condensing refrigerant evaporated in the high and low temperatureevaporating elements, means responsive to the temperature of the hightemperature evaporating element for effecting periodic operation of therefrigerant condensing mechanism, and means for automatically effecting,during each operation of the condensing mechanism, vaporareas ization ofrefrigerant in the low temperature element first and, thereafter,vaporization of refrigerant in the high temperature element.

18. In a refrigerating system the combination of first and secondevaporating elements, means for supplying liquid refrigerantpreferentially to the first element and secondarily to the secondelement, and means responsive to a relatively low temperature of therefrigerant dlscharged from the first evaporating element for admittingliquid refrigerant to said second evaporating element and responsive toa relatively high temperature for passing refrigerant vaporized in thefirst element to said second element.

19. In a refrigerating system, the combination of first and secondevaporating elements, means for condensing refrigerant vaporized in saidelement, means for supplying the condensed refrigerant to theevaporating elements so that it flows into the first evaporating elementuntil a predetermined amount is contained therein and thence into thesecond evaporating element, means for storing a predetermined quantityof condensed refrigerant in a portion of the system other than thesecond element, and a thermostatic device exposed to the refrigerantdischarged from the first element for controlling the storage ofrefrigerant in said storing means, said device being responsive to arelatively high temperature of the refrigerant for effecting storage ofrefrigerant whereby condensed refrigerant is delivered to the firstevaporator elementfor vaporization and being responsive to a relativelylow temperature of the refrigerant for rendering the storing meansineffective to store said quantity of refrigerant whereby condensedrefrigerant is delivered to the second evaporating element I forvaporization.

LESLIE M. BUCHANAN.

CERTIFICATE OF CORRECTION. Patent No 2,I 5,95b,. October 25, 19

' LESLIE B. M. BUCHANANO It is hereby certified that error appears inthe printed specification of the above numbered patent requiringcorrection as follows: Page 5, second column, line 11, afterthe'syllable "wardly" and before the comma insert the word and; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case. in I the Patent Office.

Signed and sealed this 6th day of December, Aa D, 1958.

Henry Van Arsdale (Seal) Acting Comniissioher of Patents.

